For most workflows, GPT-6 Astra is the stronger default — openai's frontier answer to fable 5.1 — computer-use and agentic-coding leader at $10/$50.
The safest GPT-6 Astra vs Claude Mythos 5.1 default, the cheaper option worth trying first, and the specialist pick — before you read the detail below.
GPT-6 Astra is the strongest answer here for GPT-6 Astra vs Claude Mythos 5.1 — pick it when quality of output matters more than the $10.00/1M/1M input you pay for it.
Claude Sonnet 5.5 handles the same job for about 80% less per token. Start here and only move up if the output is not good enough.
Claude Mythos 5.1 is the fastest of these for GPT-6 Astra vs Claude Mythos 5.1 — worth it when latency is what the reader notices, not the last few points of reasoning depth.
GPT-6 Astra leads on coding with a score of 99 vs 99 for Claude Mythos 5.1.
GPT-6 Astra has the larger context window: 1.05M vs 1M for Claude Mythos 5.1.
Both models are similarly priced — the decision comes down to capability, not cost.
GPT-6 Astra is the safer default: it is built for computer and browser use, long-horizon agentic coding, and frontier math and science work, which covers most of what people bring to this comparison.
Switch to Claude Mythos 5.1 when your work is mostly vetted frontier cybersecurity and life-sciences research at the absolute capability ceiling; on that narrower brief it is the better tool.
Both models serve different primary workflows — GPT-6 Astra for computer and browser use and long-horizon agentic coding, Claude Mythos 5.1 for vetted frontier cybersecurity and life-sciences research at the absolute capability ceiling — so running each where it has a clear edge often beats forcing one to do both.
Switch the scoring lens to see whether the GPT-6 Astra vs Claude Mythos 5.1 answer changes when cost, speed, or long-document depth leads the decision.
OpenAI / Premium / Sep 4, 2026
OpenAI's frontier answer to Fable 5.1 — computer-use and agentic-coding leader at $10/$50.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
You are cost-sensitive or latency-bound — GPT-5.6 Sol is a fifth of the price — or you need it today in an Enterprise workspace, where it is off by default, or for offensive-security work, which it refuses outside OpenAI Daybreak.
Where the GPT-6 Astra vs Claude Mythos 5.1 recommendation shifts once you weigh price or latency differently.
OpenAI's frontier answer to Fable 5.1 — computer-use and agentic-coding leader at $10/$50.
Fable 5.1 with the safeguards lifted — partner-only, 60.9% Terminal-Bench 4.0.
List prices and published scores — the numbers this page's pick is built from.
| Model | Input | Output | Est. month | Context | Speed | Coding | Writing | Research |
|---|---|---|---|---|---|---|---|---|
| GPT-6 AstraOpenAI | $10.00/1M | $50.00/1M | $200 | 1.1M tokens | Deliberate | 100 | 97 | 100 |
| Claude Mythos 5.1Anthropic | $10.00/1M | $50.00/1M | $200 | 1M tokens | Deliberate | 100 | 97 | 99 |
Scores out of 100 — how we evaluate models. “Est. month” is 10M in / 2M out at list price: a ceiling, no discounts.
Why each one is on the shortlist for GPT-6 Astra vs Claude Mythos 5.1, what it is genuinely good at, and where we would steer you away from it.
Our pick for GPT-6 Astra vs Claude Mythos 5.1. It scores 100/100 on the coding axis we weight this page by, and nothing else in this shortlist matches it on output quality.
OpenAI's September 3, 2026 frontier release — the first GPT-6 model and OpenAI's answer to Claude Fable 5.1 two days earlier. State of the art on computer use (OSWorld 2.0 72.6% in ~47% less time than GPT-5.6 Sol), agentic coding (Terminal-Bench 4.0 57.9%), and frontier math (FrontierMath Tier 4 97.6%). $10/$50 per 1M tokens, 1.05M context, 128K output, knowledge cutoff April 30, 2026.
You are cost-sensitive or latency-bound — GPT-5.6 Sol is a fifth of the price — or you need it today in an Enterprise workspace, where it is off by default, or for offensive-security work, which it refuses outside OpenAI Daybreak.
The new computer-use and agentic-coding ceiling, and OpenAI's first model priced like a Mythos-class Claude. Astra beats Claude Fable 5.1 on Terminal-Bench 4.0 (57.9% vs 55.8%), Terminal-Bench Science (64.6% vs 52.6%) and FrontierMath Tier 4 (97.6% vs 87.8%), and it is the only model with a credible OSWorld 2.0 result above 70%. It loses to Fable 5.1 on Humanity's Last Exam and on Artificial Analysis's index, costs five times GPT-5.6 Sol, and ships without a SWE-bench number. If your work is computer use, browser agents or math, it is the pick; for everyday coding at scale, Sol at $2/$10 remains the value default.
Full pricing, benchmark table and release notes on the GPT-6 Astra page.
Here for latency: it answers fastest of anything listed for GPT-6 Astra vs Claude Mythos 5.1, at 100/100 on coding.
The unrestricted twin of Claude Fable 5.1 — the same model with safeguards lifted in high-risk areas, released September 1, 2026 to vetted cybersecurity and life-sciences organisations under Anthropic's trusted-access programme. Scores 60.9% on Terminal-Bench 4.0, the highest agentic-coding result Anthropic has published.
You don't hold vetted trusted access, or your work never trips Fable 5.1's safeguards — the two models are otherwise identical.
The highest published agentic-coding score anywhere — 60.9% on Terminal-Bench 4.0 — but you almost certainly cannot get it. Mythos 5.1 is Fable 5.1 with safeguards lifted, gated to vetted cybersecurity and life-sciences organisations. Unless you hold trusted access and hit refusals that block real research, Fable 5.1 is the same model at the same price.
Full pricing, benchmark table and release notes on the Claude Mythos 5.1 page.
UseRightAI recommendations are based on practical decision factors people actually feel in day-to-day use.
Newsletter
We email when the GPT-6 Astra vs Claude Mythos 5.1 pick changes, when one of these models moves on price, or when something new displaces the current leader.
No spam. Useful updates only. Affiliate disclosures always clearly labeled.
GPT-6 Astra wins on more of the categories we score — coding, research, long context — so it is the better default of the two. Claude Mythos 5.1 is the better pick when your work is mostly vetted frontier cybersecurity and life-sciences research at the absolute capability ceiling. Neither is universally "better": GPT-6 Astra is aimed at computer and browser use and long-horizon agentic coding, Claude Mythos 5.1 at vetted frontier cybersecurity and life-sciences research at the absolute capability ceiling.
Both models are similarly priced at $10/1M input tokens. The decision should come down to capability, not cost.
GPT-6 Astra has the larger context window at 1.05M tokens vs Claude Mythos 5.1's 1M. For large document analysis, GPT-6 Astra is the stronger pick.
GPT-6 Astra and Claude Mythos 5.1 are similarly matched on coding. Claude Opus 5.5 is the overall coding leader in this directory at 100/100.
Both GPT-6 Astra and Claude Mythos 5.1 have similar speed profiles — rated deliberate. Neither will be the bottleneck if latency is your deciding factor.
$10/$50 per 1M — two and a half times GPT-5.6 Sol's $4/$20 promotional rate, five times GPT-6.1 Sol's $2/$10, and the same premium as Claude Fable 5.1; Fast mode doubles it again. Trails Claude Fable 5.1 on Humanity's Last Exam with tools (57.2% vs 65.0%) and on the Artificial Analysis Intelligence Index (61.2 vs 65.7). OpenAI published no SWE-bench Verified or SWE-bench Pro figure at launch, so it does not appear on our SWE-bench leaderboard. Avoid it if you are cost-sensitive or latency-bound — GPT-6.1 Sol is a fifth of the price — or you need it today in an Enterprise workspace, where it is off by default, or for offensive-security work, which it refuses outside OpenAI Daybreak. That is the main case for looking at Claude Mythos 5.1 instead.
Not generally available — restricted to vetted US organisations under Project Glasswing. No advantage for ordinary work; Fable 5.1 is the same model at the same price for everyone else. Same deliberate, high-latency profile and premium pricing as Fable 5.1. Avoid it if you don't hold vetted trusted access, or your work never trips Fable 5.1's safeguards — the two models are otherwise identical. Against GPT-6 Astra specifically, the two are close enough on capability that price and speed decide it.
Take a moderate workload of 10M input and 2M output tokens a month. GPT-6 Astra runs $200.00 (at $10/1M in and $50/1M out); Claude Mythos 5.1 runs $200.00 (at $10/1M in and $50/1M out). The gap is small enough that price should not decide this one. Output tokens dominate the bill on both, so prompt length matters far less than response length.
Yes, and for most teams that beats picking one. A common split is GPT-6 Astra for computer and browser use and long-horizon agentic coding, with Claude Mythos 5.1 handling vetted frontier cybersecurity and life-sciences research at the absolute capability ceiling. Since GPT-6 Astra is both the stronger and the cheaper option here, a split mainly makes sense if Claude Mythos 5.1 covers a capability you specifically need.